Manual renewals always generate a new basket. It's likely that auto recurring payments don't as they have to be linked to a basket to validate (their IPNs always include the basket id).

Where are you looking for invoices? They should be on the invoices page that you can reach from the bottom of the subscriptions tab. They should also ideally get an invoice from the payment gateway directly.

For CBSubs the basket and the invoice are the same thing. Payments are tied to a basket. Invoices are not based off payments. It creates a new basket for manual renewals as it has no need to validate the basket. IPNs have to validate against the basket. I suppose it could be rewritten at some point to take the original basket and create a new one from it by clearing the id before storing, which would effectively do what you're wanting, but that's not likely to happen anytime soon as it's a pretty serious change.

Have added a feature ticket to review rewriting the behavior to see if creating a new basket per renewal would be more ideal.

#6647